Traffic signal



W. S. BAKER TRAFFIC SIGNAL Oct. 26, 1937.

Filed May 24, 1955 2 Sheets-Sheetl 3c em:

F'iled May 24, 1935 2 Sheets-Sheet 2 Patented Oct. 26, 1937 UNETED STATES PATENT oFFieE 2,096,952 7 TRAFFIC SIGNAL William s. Baker, Fort Worth, Tex.

Application May 24, 1935, Serial N0. 23,173

3 Claims.

This invention relates to new and useful improvements in traffic signals.

The trafiic signals for controlling trafiic at street intersections which are now in general use and which are generally known as stop and go signals, employ three lights, the red, green and amber. The amber light which designates a trafiic change is visible to the standing traflic which is waiting for the go signal or green light,

as well as to the moving trafdo. In some cases, when the amber light is lighted, a warning, such as a bell, is sounded to inform the traffic that a change is about to occur. In other cases, only the warning is sounded, the amber light being eliminated.

In all cases, however the warning of the trafiic change, whether it be an amber or other light, or the ringing of a bell, is visible or audible to the halted trafiic which is waiting for the go signal, or green light. It has been found that the standing trafiic will immediately start forward on the amber light, not waiting for the intersection to clear. Many accidents are due to the fact that both the moving vehicle and the 5 standing vehicle assume that the amber light gives each the right of way.

It has been found further that the pedestrian trafiic also tends to start across the street as soon as the amber light is lighted, or the warning 0 sounded. The assumption is that as soon as the traffic change is designated, the way is clear. A driver who is driving at an excessive speed or whose vehicle has faulty brakes, is forced to cross the intersection on the amber light because of his 35 inability to stop, and many accidents involving pedestrians occur because the pedestrian started across the street upon the lighting of the amber light, or the sounding of the warning. Further,

when a bell, or other warning is used the constant 0 noise of the same is objected toby the residents of the houses at the street intersection.

One object of this invention is to provide an improved trafiic signal for controlling traffic, both vehicle and pedestrian, whereby all the above dis- 5 advantages are overcome.

An important object of the invention is to provide a trafiic signal of the stop and go type which has means for informing traffic having the go signal or green light that a traffic change '5 is about to occur, said means being invisible to the halted traffic and pedestrians, whereby they are not informed in advance that a change in trafiio is to occur, thereby causing them to wait until the green light or go signal in their di- 5 rection is actually on.

Another object of the invention is to provide an improved traffic signal wherein an auxiliary lamp projecting an amber or other colored light is mounted within the casing of the green light, or go signal, said lamp being arranged to be 5 lighted for a short period just prior to the turning off of said green light, whereby an amber or other colored streak of light will appear within the area of the green light so as to warn an approaching driver that the green light is about to be extin- 10 guished.

A further object of the invention is to provide a lamp casing for projecting a green light to denote the g signal in a traffic signal, together with means for displaying a streak of colored light 16 within the area of said green light'just prior to the extinguishing of said green light, and means on the casing for preventing others than those ap-' preaching the green light from seeing said streak of light which discloses that a traifi 20 change is about to occur.

Still another object of the invention is to provide a traffic signal having a silent means for disclosing a trafiic change is to occur which is in- Visible to halted or standing vehicles and pedestrians and is visible only to the moving traflic, whereby the safety of both vehicles and pedestrians is increased and the objectionablenoise incident to the sounding of a warning is eliminated.

A construction designed to carry out the invention will be hereinafterdescrib-ed, together with other features of the invention. The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein;

Figure 1 is a front elevation of a trafiic signal constructed in accordance with the invention,

Figure 2 is an enlarged longitudinal vertical 40 sectional view of the green lamp casing of said signal,

Figure 3 is a front elevation of the same,

Figure 4 is an enlarged longitudinal sectional view of another form of the invention,

Figure 5 is a transverse vertical, sectional View taken on the line 5-5 ofFigure 4,

Figure '6 is a front elevation of the same,

Figure 7 is a schematic view showing the trafiic signals mounted at a street intersection, and

Figure 8 is a wiring diagram.

In the drawings, the numeral it designates a base plate which has a vertical post I l extending upwardly therefrom. A housing 12 issupported on the upper end of the post and this housing has the signal lamps l3 and I 4 mounted therein. The upper lamp I3 is the green or go signal while the lower lamp I4 is the red or stop signal. This lower lamp may be of any desired construction and is operated in the usual way. Each lamp is provided with a circular hood l5 which extends therefrom in the usual way.

The invention lies in the construction of the green light or go signal and as clearly shown in Figure 2 this-light comprises a circular lamp casing l6 which has. its forward end open; This open end is closed by a suitable green-colored lens IT. A concave reflector I8 is suitably mounted within the casing at the rear thereof and an electric lamp socket l9 having an electric lamp 20 therein is secured centrally of the reflector. This is the usual traflic signal lamp casing construction and it is obvious that when the lamp 20 is lighted, the go signal or green light is visible to approaching vehicles; The hood l5 extends forwardly from the casing I6, being bolted or otherwise suitably secured thereto. The hood serves to direct the light toward the approaching vehicle and also serves to some extent to prevent the driver of a standing Vehicle waiting for the traffic change from seeing such green light. However, the reflection of the green light on the inner side of the hood is visible to the driver of such vehicle. Similarly, such driver could see the reflections of an amber light if such were used, and therefore if the amber light were lighted intending only to inform approaching drivers, the standing vehicles and pedestrians would Watch for the reflection within the hood, and thus, trafiic would begin moving before the intersection is clear.

To overcome this difiiculty and to make the amber or other warning light, which designates a traffic change, entirely invisible to the standing or haltedvehicles and pedestrians, and clearly visible to the moving trafiic, an opening 2| is drilled or cast in the lens IT. A cylindrical casing or tube 22 is mounted in this opening and extends rearwardly therefrom. A lens 23 which may be of any colored glass is secured in the rear of the tube 22 and a comparatively small electric lamp 24 is located directly behind this lens. The lamp socket 25 is supported in a suitable bracket 26 depending from the underside of the top of the casing.

In operation, the electrical circuit is arranged to alternately light the red and green lights I 3 and I4. The length of time which each remains lighted is optional.

It is preferable to mount four signal posts A, B, C, and D at each street intersection, as shown in Figure 7. Each signal is for one direction of trarfic, that is, the signal A is for traflic moving in the direction of the arrow A, B- for arrow B, C for arrow C and D for arrow D'. However, it is pointed out that any number of signal posts may be used.

Assuming that the traffic moving north and south has the go signal, the green lights l3 in the signals B and C are lighted, while the red lights 14 in the signals A and D are lighted. Thus east and west traffic is at a standstill. The vehicles thus waiting for the lights to change cannot see the lens I! of the green lights in the lamps B and C but can see only the reflection on the inside of the hood. The same is true of pedestrians who are waiting to cross the northsouth street, as they can only see the lights of the signals A and D. i

When the trafiic change is about to occur, the

small lamp 24 within the lamp casing I6 is lighted. At this time the green lamp Ed, the rays of which project thru the green lens H, is still lighted. Since this lens is provided with an opening 2| the rays of the small lamp 24 project thru this opening and to the driver approaching this green light, a spot of different colored light is visible within the area of the green lens 57. This immediately warns him that a traflic change is about to occur and he can bring his car to a stop or speed up and cross the intersection before such change. The drivers of the standing or halted vehicle waiting for the green light on. the east-west street have no knowledge of the change until it actually occurs. They cannot see the reflection in the hood of the spot of light which appears in the area of the lens. If necessary, the inner face of the hood may be painted a slate color, or other color which decreases reflection. The lamp 24 is not powerful enough to change the green color of the reflection within the hood and therefore, even tho one of the drivers of the halted vehicles watches the reflection, he cannot possibly tell just when the green light is to be extinguished. Thus, only the drivers of the moving vehicles have any knowledge of the coming change, and they may govern their actions accordingly. The pedestrians standing on the curb waiting for the light to change are also prevented from knowing just at what time the traffic change is to occur and, therefore must wait until the lights actually change. With this arrangement the intersection is always clear before the tra-flic which has just received the go signal begins to move and also before the pedestrians begin to cross the street. The length of time which the small lamp remains lighted may vary but it has been found that three seconds is a sumcient time, altho the invention is not to be so limited. It is pointed out that the small lamp 24 is extinguished when the lamp 2! is extinguished. If desired, the small lamp may be arranged to wink, or be lighted and extinguished three or four times in rapid succession rather than burning constantly.

Any suitable electrical hook-up may be employed, but the circuit shown in Figure 8 has been found satisfactory. In this diagram, a switch panel 42: has three switches ii, .2 and 43 mounted thereon. These switches are of the usual automatic operating type. The switches 45 and 42 are connected by wires 4m and 42a with the source of electrical supply. When the switch 4! is closed electrical current flows through a line 4) which is connected by a wire Ma. with the red light l4 controlling east and west bound traffic at the intersection. The other side of the light M is grounded through a wire M1) to a common ground wire 44, whereby the circuit to this red light is closed.

The line M2) is also connected to the green light i3 which controls north and south traffic by a wire 53a. and the opposite side of this light is connected with the ground wire 44 by a wire E322. Therefore, when the switch M is closed, the red light controlling east and west traffic and the green light controlling north and south trafiic are lighted simultaneously.

Just prior to a traflic change, the switch 43 is closed, while the switch 4! is still closed. The closing of the switch 43 closes a circuit to the lamp 2 3 of the lighted green signal I 3, through Wires 43a, 24a, 24b, l3a and 45b, whereby the Warning lamp is lighted.

At the traffic change, the switches 4| and 43 are opened and the switch 42 closed simultane ously whereby the green light I3 and lamp 24 controlling north and south trailic are extinguished, as is the red lamp l4 controlling east and west traffic. Closing of the switch 42 causes current to flow through a wire 42b, and wire I30 to the green light I 3 which controls east and west traflic. The circuit to this lamp is completed through a wire l3d, which connects to wires Mb and common ground wire 44. At the same time, the red light [4 controlling north and south traffic is lighted, through the wire Me which connects with the wire 4217. This red light is grounded through the wire 1411 which ties into the wire I3b and common ground 44. Thus, when the switch 42 is closed the green light for east and west trafiic and red light for north and south trafiic are lighted.

Just prior to trafiic change, the switch 43 is again closed to close the circuit to the signal lamp 2 of the burning green light I3 through wires 43a, 24c, 24d, 13c and 42b, whereby this warning lamp is lighted. The switches 42 and 4-3 are then opened simultaneously with the closing of the switch 41 and the cycle is repeated.

In Figures 4 to 6 another form of the invention is shown. In this form, the small lamp 24, together with the tube 22 and opening 2! in the lens is eliminated. Instead, the lamp casing I is constructed in the usual way and an elongated, narrow housing 30 is suspended within the hood 55. An elongated lamp 32 is screwed into a socket mounted in the upper side of the hood and deends into the housing. A suitable, colored lens 33 covers the front of the housing and when the lamp 32 is lighted, an elongated stream of colored light appears in the area of the green light. When the lamp 32 is not burning the reflections of the green light against the inner sides of the hood are strong enough to make the housing substantially invisible. The operation of this form is the same as the first form and a detailed description is considered unnecessary.

It is pointed out that the warning is silent thereby eliminating the noise incidental to the ringing of a bell. The warning is only conveyed to the trafiic approaching the green light and therefore the intersection is clear before the halted traiiic begins to move or pedestrians start across the street which greatly increases the safety of both vehicles and pedestrians.

What I claim and desire to secure by Letters Patent is:

1. A traffic signal system including, a red lamp, a green lamp, means for alternately lighting the lamps to provide separate light beams to control the movement of traffic at an intersection, means for displaying a distinct beam of light of another color confined in the beam of light of the green lamp by maintaining the total beam,

when viewed laterally, of green color, whereby anv approaching driver is warned of the traflic light change which is about to occur, anda hood projecting outwardly from the lens of the green lamp, whereby said warning light is invisible to the driver of a vehicle standing on the intersecting street, and also to a pedestrian waiting to cross the street through which trafiic is moving.

2. A trafi'ic signal including means for displaying a green light at intervals, comprising, a lamp casing, a lamp within said casing, a greencolored lens through which the rays of said lamp are projected, and an elongated narrow lamp casing and lamp suspended within the hood in front of said lens, and means for lighting the lamp in said elongated casing just prior to the extinguishment of the first named lamp, to display a distinct source of light of a different color within the field of the rays of the lamp passing through the green lens, but in such manner that when viewed laterally the total beam appears green, whereby a driver approach-' ing the signal in the direction of moving traffic only is warned that a traffic change is about to occur.

3. Means for regulating trafiic movement at an intersection, comprising, a hooded go indicating light means of a particular color, the source of which is envisioned only in the direction of traihc movement, but the beam of said.

light being visible to a pedestrian or driver of a vehicle waiting at the intersection to cross, and a supplemental trafiic change indicating light means of lesser intensity and distinctive color displayable confinedly in the beam of said go indicating light before the time of traffic change and being extinguished when said go indicating light is extinguished, the source of said supplemental light being directed so as to be envisioned only in the beam of said go indicating light in the direction of traific movement and said beam when viewed laterally being maintained in its original color.

WILLIAM S. BAKER. 

